The present invention relates to a method for welding two polyamide plastics using a primer, the primer containing at least one polymer synthesized from at least one maleic anhydride or maleic anhydride derivative. The invention also relates to correspondingly welded products.

A resin-rubber composite in which a polyamide-based resin-molded product or a polyphenylene sulfide-based resin-molded product is directly vulcanization-bonded to a peroxide-crosslinkable nonpolar rubber composition, which forms a rubber layer, without interposing an adhesive, wherein both resin-molded products have a polymerized film with a radical, which is formed by activating the surface of the product, in the case of polyamide-based resin-molded products, by low-pressure plasma treatment by a microwave method using inert gas, or by activating the surface of the product, in the case of polyphenylene sulfide-based resin-molded products, by low-pressure plasma treatment by a microwave method using active gas, and then performing low-pressure plasma treatment by a microwave method using a hydrocarbon-based monomer in both cases. The resin-rubber composite can be effectively used for drum seals, automobile parts such as side cover seals for transmissions, anti-vibration rubber, resin rubber laminate hoses, and the like.